The Medical Practitioners Board is facing legal action over failing to protect the women, who may have been deliberately infected by a doctor who had the virus at a Melbourne abortion clinic.

At least seven women allegedly infected with hepatitis C will take legal action against the Medical Practitioners Board, anaesthetist Dr James Latham Peters and the surgery where he worked -Croydon Day Surgery.

He was suspended on February 15, two weeks after the Medical Board of Victoria was notified and two months after the health department became aware that three women who had contracted hepatitis C had been to the Croydon clinic.

Besides those three women, who are represented by law firm Slater & Gordon, 12 others were also identified last month by the Department of Human Services (DHS) as having been infected.

The number of victims is likely to swell with the DHS confirming on Sunday it has extended the scope of its investigation from 18 months to four years.

Lawyer Paula Shelton said the process by which the board regulates doctors needed to be overhauled.

The primary objective of the board's health program is to protect the public, but with sick doctors it also balances that with the importance of restoring doctors to health so they are able to practice safely, she said.